Review support is in the price

A review can come years after the claim is paid,1Source 1A tax authority can review a claim after it has been paid, within time limits set by law: Internal Revenue Code section 6501 (United States); Finance Act 1998 Schedule 18 paragraphs 24 and 46, via HMRC Enquiry Manual EM1510 and Compliance Handbook CH51300 (United Kingdom); Taxes Consolidation Act 1997 section 959AA, via Revenue Notes for Guidance Part 41A (Ireland); Income Tax Act section 152(3.1) and (4) (Canada); Income Tax Assessment Act 1936 section 170, Income Tax Assessment Act 1997 section 355-705 and the ATO, Request an amendment to a business or super tax return (Australia); Tax Administration Act 1994 section 108, via Inland Revenue SPS 20/03 (New Zealand); Income Tax Act 1947 section 74 (Singapore). More detail on your country page. and the cost of answering it is hard to predict. A fee that includes review support, with the clause saying what it covers and for how long, removes that uncertainty. It also tells you something: an adviser who commits in advance to defending the claim expects it to hold. Support is help, not a promise to pay any tax, but help is what you will need.

• Find the clause. "Support is available" is not the same as "support is included".
• Check what it covers: correspondence, meetings, revised calculations, and work on new information from the tax authority.
• Check how long it lasts after filing, and that it does not end with the engagement.
• Check who does the work and whether the working papers are kept for the period a review can arrive in.
• Compare the fee with proposals that exclude support, adding a realistic cost for support to those.